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It's based on v7.0-rc3. It's too intrusive for a >>>>> 7.0 hotfix, so we'll only be able to fix/reduce the regression in 7.1. I >>>>> hope it's acceptable given it's a non-standard configuration, 7.0 is not >>>>> a LTS, and it's a perf regression, not functionality. >>>>> >>>>> Ming can you please retest this on top of v7.0-rc3, which already has >>>>> fb1091febd66 ("mm/slab: allow sheaf refill if blocking is not >>>>> allowed"). Separate data point for v7.0-rc3 could be also useful. >>>>> >>>>> [1] https://lore.kernel.org/all/c6a01f7e-c6eb-454b-9b9e-734526dd659d@kernel.org/ >>>>> >>>>> Signed-off-by: Vlastimil Babka (SUSE) >>>>> --- >>>>> Vlastimil Babka (SUSE) (3): >>>>> slab: decouple pointer to barn from kmem_cache_node >>>>> slab: create barns for online memoryless nodes >>>>> slab: free remote objects to sheaves on memoryless nodes >>>> >>>> Hi Vlastimil and Guys, >>>> >>>> I re-run the test case used in https://lore.kernel.org/all/aZ0SbIqaIkwoW2mB@fedora/ >>>> >>>> - v6.19-rc5: 34M >>>> >>>> - 815c8e35511d Merge branch 'slab/for-7.0/sheaves' into slab/for-next: 13M >>>> >>>> - v7.0-rc3: 13M >>> >>> Thanks, that's in line with your previous testing of "mm/slab: allow sheaf >>> refill if blocking is not allowed" making no difference here. At least we >>> just learned it helps other benchmarks :) >>> >>>> - v7.0-rc3 + the three patches: 24M >>> >>> OK. So now it might be really the total per-cpu caching capacity difference. >> >> >> I have also observed a performance regresssion for Linux v7.0-rc for some >> graphics related tests we run. I bisected to ... >> >> # first bad commit: [e47c897a29491ade20b27612fdd3107c39a07357] slab: add >> sheaves to most caches > > Hi, Jon > > Thanks for the reporting. > This first bad commit is surprising. In theory, this commit seems couldn't hurt > performance. > Could you possibly manually switch commits to verify this bad commit again, > without using git bisect? So I went back and checked out commit e47c897a29491ade20b27612fdd3107c39a07357 ("slab: add sheaves to most caches") confirmed that the problem exists there and then reverted that and confirmed that I no longer see the problem. Jon -- nvpublic